My Tach Installation (Stihl MS-441 R C-M) -- Looks nice, but...bad idea?

[Officer's Match]

Really nice looking mod, well done indeed. Wonder about those peak rpm readings, almost see a tad low to me, but I could easily be wrong.

 

[Terry Syd]

So Terry are you saying you can tweek the 441C MTorinc carbs ?.

LOL, no I wouldn't be so bold as to say that. I've never even run a 441 MTronic let alone checked out the electronic schematic. However, I was an electronic technician for 7 years and I did tweak a few circuits in my time, including the electronic fuel injection on a 280Z. If you can get me a schematic of the MTronic system, I'll see if I can come up with a few ideas. It would be cool to tweak an input just enough to not compromise the computer logic, but enough to piss off the EPA and give a bit more power.

What I was referring to was that a tach can give you an OBJECTIVE indication of an increase in power. Kinda like doing a jetting change and see a small increase in rpm or speed down the back straight. You can't really pick up the increase in the sound or the tactile sensation, but the gauges don't lie.

In regards to an increase in low end power, here's something I went through. Say you have an engine that makes the best horsepower at 10,000 rpm and max torque at 7,000. So you go ahead and put a big bore kit on it which should increase the torque, you also remove the base gasket and increase the compression which should increase the torque. Since you decreased the time/area of the transfers a bit, the torque peak should be a bit lower. Further, you increased the intake timing and it doesn't go into backflow when it bogs.

After all the mods you notice that it bogs and the clutch slips at the same 5,500 rpm as before the mods. Hang on, some things not right, the clutch should be slipping at a higher rpm if the low end torque has increased. A change in ignition timing either way doesn't help - logically, the fuel mixture is the next step.

You start increasing the low speed circuit flow (I'm referring to drilling out the jets on the Zama carb) and you start picking up more low end torque. When you finish tweaking the carb the engine doesn't 'bog', it just stops cutting when the clutch starts slipping at 6,000 rpm.

The tach allows you to get an OBJECTIVE reading of what the engine is doing. I'm sure that many chainsaw racers can pick up those small gains, but a hack like me needs the extra information of the tach to keep me from fooling myself.

 

[XSKIER]

I just re-read this whole thread but no mention of the wires that are sticking out of the saw. Does that tack need external power?

 

[KG441c]

I just re-read this whole thread but no mention of the wires that are sticking out of the saw. Does that tack need external power?

Trailtech.net The unit is inductive or 12v operated. Has a 5yr battery installed from what i gather on Trailtechs site

 

[shootingarts]

LOL, no I wouldn't be so bold as to say that. I've never even run a 441 MTronic let alone checked out the electronic schematic. However, I was an electronic technician for 7 years and I did tweak a few circuits in my time, including the electronic fuel injection on a 280Z. If you can get me a schematic of the MTronic system, I'll see if I can come up with a few ideas. It would be cool to tweak an input just enough to not compromise the computer logic, but enough to piss off the EPA and give a bit more power.

What I was referring to was that a tach can give you an OBJECTIVE indication of an increase in power. Kinda like doing a jetting change and see a small increase in rpm or speed down the back straight. You can't really pick up the increase in the sound or the tactile sensation, but the gauges don't lie.

In regards to an increase in low end power, here's something I went through. Say you have an engine that makes the best horsepower at 10,000 rpm and max torque at 7,000. So you go ahead and put a big bore kit on it which should increase the torque, you also remove the base gasket and increase the compression which should increase the torque. Since you decreased the time/area of the transfers a bit, the torque peak should be a bit lower. Further, you increased the intake timing and it doesn't go into backflow when it bogs.

After all the mods you notice that it bogs and the clutch slips at the same 5,500 rpm as before the mods. Hang on, some things not right, the clutch should be slipping at a higher rpm if the low end torque has increased. A change in ignition timing either way doesn't help - logically, the fuel mixture is the next step.

You start increasing the low speed circuit flow (I'm referring to drilling out the jets on the Zama carb) and you start picking up more low end torque. When you finish tweaking the carb the engine doesn't 'bog', it just stops cutting when the clutch starts slipping at 6,000 rpm.

The tach allows you to get an OBJECTIVE reading of what the engine is doing. I'm sure that many chainsaw racers can pick up those small gains, but a hack like me needs the extra information of the tach to keep me from fooling myself.

Ummm, very interesting although you lost me about halfway through the second paragraph! There was a time I trusted seat of the pants more, I knew if my dirt track engine was 50 RPM off at 78000, but there was an almost organic connection between me and that car. I routinely did the impossible with it. Saws I don't have the same feel for and I'm a whole lot deafer, partially because of listening to that car engine scream. I need a tach too and plan to purchase one after the first, lots of non-necessities being put off till after the holidays!

When it comes to tweaking the electronics I never tried. I did get a chuckle out of a friend with a new Volvo back in the eighties, first car I ever saw that talked to you. He thought the snooty sounding broad was pretty cool for a month or two and then decided he couldn't stand her voice which had no setting to be changed. Next time I saw him he called me out to his car. He had done some tweaking and had her talking like a sweet southern girl!

Hu

 

[MtnMike]

I just re-read this whole thread but no mention of the wires that are sticking out of the saw. Does that tack need external power?

No, the tach does not need an external power source. The wire you see is the tach's pickup lead that is still at it's original factory length. I haven't cut it down to size yet to fit inside the saw. It snakes out of the cover and then back in again to connect to the spark plug wire. I'll cut it down today since I'm finally going to be able to get into some wood!

By the way, according to the manufacturer, this little tach is waterproof. Cool. Being that well sealed, it should stand up to that incoming air stream I was originally worried about...and falling snow or whatever other moisture might get on the saw. (Bad aim with the fuel can, maybe. )

For some comparison, here is a video of the same tach on my Craftsman 358.356332 saw. (No idea what kind of saw this actually is...more badge engineering...is it a Poulan?) This is an old saw I inherited from my dad when he passed away. I remember him using it on Boy Scout service projects in the early 80s. Not the world's greatest saw, but I hang on to it for sentimental reasons, I guess.

Please no lectures on the poor tuning. I'm just on the early part of the saw-tuning learning curve (thanks to you guys and this forum), and I have not done a THING to this saw in years. It doesn't have an electronic ignition and is the only other saw I have here at the house, so it was a good test machine.

 

[Stihlman441]

This is the ones i use looks the same,this is on a 261 with muff modd.

 

[Andyshine77]

LOL, no I wouldn't be so bold as to say that. I've never even run a 441 MTronic let alone checked out the electronic schematic. However, I was an electronic technician for 7 years and I did tweak a few circuits in my time, including the electronic fuel injection on a 280Z. If you can get me a schematic of the MTronic system, I'll see if I can come up with a few ideas. It would be cool to tweak an input just enough to not compromise the computer logic, but enough to piss off the EPA and give a bit more power.

What I was referring to was that a tach can give you an OBJECTIVE indication of an increase in power. Kinda like doing a jetting change and see a small increase in rpm or speed down the back straight. You can't really pick up the increase in the sound or the tactile sensation, but the gauges don't lie.

In regards to an increase in low end power, here's something I went through. Say you have an engine that makes the best horsepower at 10,000 rpm and max torque at 7,000. So you go ahead and put a big bore kit on it which should increase the torque, you also remove the base gasket and increase the compression which should increase the torque. Since you decreased the time/area of the transfers a bit, the torque peak should be a bit lower. Further, you increased the intake timing and it doesn't go into backflow when it bogs.

After all the mods you notice that it bogs and the clutch slips at the same 5,500 rpm as before the mods. Hang on, some things not right, the clutch should be slipping at a higher rpm if the low end torque has increased. A change in ignition timing either way doesn't help - logically, the fuel mixture is the next step.

You start increasing the low speed circuit flow (I'm referring to drilling out the jets on the Zama carb) and you start picking up more low end torque. When you finish tweaking the carb the engine doesn't 'bog', it just stops cutting when the clutch starts slipping at 6,000 rpm.

The tach allows you to get an OBJECTIVE reading of what the engine is doing. I'm sure that many chainsaw racers can pick up those small gains, but a hack like me needs the extra information of the tach to keep me from fooling myself.

Hack my ass.

 

[Eccentric]

That Craftsman saw is indeed a Poulan. Probably a 3.3 labeled 3300 (or a similar model in that series). It's a well made saw built in the late 1980's or early 1990's. Definitely does have electronic ignition.

 

[MtnMike]

That Craftsman saw is indeed a Poulan. Probably a 3.3 labeled 3300 (or a similar model in that series). It's a well made saw built in the late 1980's or early 1990's. Definitely does have electronic ignition.

You are correct, labeled as a 3.3ci and it does have electronic ignition. I should have said it's not some variety of auto tune.

And it actually is a pretty good saw. It's been around a long time, and still runs pretty dang well. Could use some tuning of course...

 

[MtnMike]

I made a small change to my mounting method, if anyone is interested.

Originally I secured the tach with two ordinary Phillips-head screws and nuts:

I found some hardware at the hobby shop that cleaned up the mounting a little:

Here's what I used:

What these guys call "blind nuts" I've always called "tee nuts". Whatever...they're the same thing. Cut and/or file off the teeth on the underside of the blind nuts and then push them into the screw holes from the back side of the tach (it will be a TIGHT fight). Oh, and 3/4" is too long for the screws, you'll have to cut them down.

Not a big deal, but it is a little more elegant. Just thought I'd share.

Have a happy new year!!

 

[shootingarts]

Seems the thread has kind of ran it's course but with the guys with experience with these tach's here I want to ask a couple questions please:

I want to put a tach on my Makita 6401 for tuning. Permanent or not doesn't really matter but my hearing just doesn't leave me confident trying to tune by ear. I don't have the mtronic type full computer ignition but I do have a limiting coil according to what I read, shouldn't be an issue before the rated 13,500 RPM or better though.

My questions concern if the tach will work properly with that coil running unloaded below 13500 or wherever the coil limiter kicks in, and will it work properly under load in a heavy cut? Looking at other tach's too, $85 and $139 respectively. I don't know that any of them are superior for what I want to do and the TTO is half the price, should make it twice the fun to play with!

Thanks for any assistance!

Hu

 

[KG441c]

I put the tto tach on my 441c and it works great!

 

[shootingarts]

I put the tto tach on my 441c and it works great!

Thanks! Pretty sure for forty bucks I'm going to have to give it a try. Running my saw very fat now because I can't tell what is going on. Hope to tune it to a few hundred RPM before the tach goes squirrelly with the coil playing games and/or RPM in a heavy cut with a sharp chain. I want changing out the top end to be a planned event!

Hu

 

[Philbert]

Very nice looking install.

Where is the best place to find these types of tachs? Price range?

Thanks.

Philbert

 

[shootingarts]

Phil,

You can buy these things directly from the source, don't know if they are a builder or importer but they have them at an excellent price, haven't checked shipping yet. Find a few other things to buy there and shipping on orders over $100 is free. Don't know about posting links and such but a search on the tach/hour meter will turn them up pretty high on the list. You get a little more warranty on the battery that way since you don't lose the time it was sitting on someone else's shelf. Too, as long as there isn't reason not to I generally prefer cutting out the middle men. Not always but often the middle men are costing both me and the original source money.

Available in orange, black, or silver for under forty bucks not including shipping. The same source has other digital instrumentation too.

Hu